I love both NiamhMaire and and KeiraMae! NiamhMaire doesn't flow as well since both names are one syllable- have you considered NiamhMary? I like that you're using Irish names to honour your heritage. Niamh is one of my favourite Irish names (I also love Orflaith and Roisin) and I like the sleek, modern sound of Keira (I do think of Keira Knightley right away, but I've probably seen Pride and Prejudice dozens of times).